Electroplating apparatus



Feb. 8, 1944. J. 5. NACHTMAN I 2,341,158

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ELECTROPLATING APPARATUS Original Filed Jan. 16, 1939 3 Sheets-Sheet 3Jblmfmiman Patented Feb. 8, 1944 mthltt all ELECTROPLATING APPARATUSJohn S. Nachtman, Youngstown, Ohio Original application January 16,1939, Serial No.

251,065. Divided and this application March 17, 1942, Serial No. 435,030

4 Claims. (or. 204-206) This invention relates to electro-baths, andparticularly, to the handling of strip material while subjecting it toan electro-treating process, such as electroplating. I have particularreference to suitable apparatus for continuously electroplating ortreating meta1 strip and the like. This application is. a division of mycopending application Serial No. 251,065, filed January 16, 1939.

I have found that there are many difficulties encountered in providing asuitable arrangement for the purposes enumerated. In electro-treatment,the strip will constitute one of the electrodes (in plating, thecathode) and other means will constitute the other electrode (inplating, the anode).

Some of the difficulties with prior methods and apparatus forcontinuously treating metal. strip occur because the strip is notperfectly straight (i. e., possesses camber), as a result of which itundergoes a lateral sliding motion as it passes over the various rollsand contacts the Walls of the plating tank and other parts of theapparatus, resulting in damage thereto. Since the anodes are located ina predetermined central position in the plating tank, this sidewiseshifting of the strip results in the deposition of a non-uniformelectro-deposit on the strip.

It is accordingly a general object of my invention to provide acommercially practical solution of these difficulties.

More specifically, it is an object of my invention to provideelectroplating apparatus for strip material that will automaticallycenter the strip in its passage through the bath and prevent it fromcontacting the sides of the electro-tank.

These and other objects of my invention will appear to those skilled inthe art from the drawings, the description, and the appended claims.

Although for the purpose of illustration, I particularly refer toelectroplating operations, it should be understood that many of thenovel features of this invention are equally applicable toelectro-pickling and other types of electrobath treating operations.

In the drawings:

Figure 1 is a side elevational view of an electroplating apparatusembodying my invention.

Figure 2 is a vertical sectional view taken along the line 2-2, ofFigure 1, looking in the direction of the arrows in ,this figure; therelativ location of the contact roll assemblies, the submerged rollassembly, the anodes, the bus bar assembly and electrolyte conduits areshown.

Figure 3 is a vertical longitudinal sectional View taken substantiallyalong the line 3-3 of Figure 2, looking in the direction of the arrows.

Figure 4 is a side elevational view, with parts broken away of acombined squeegee roll and strip centering roll assembly.

Figure 5 is a top plan view of the structure shown in Figure 4.

Figure, 6 is a view in elevation, with parts broken away, looking at theleft hand end of the structure shown in Figure 4, with the end plateremoved.

Figure 7 is a cross sectional view taken substantially on the line 1---!of Figure 6.

Figure 8 is a diagrammatic view of the electric circuitand the electricunits employed in the structure of Figures 4-7, inclusive.

With continued reference to the drawings, wherein like referencecharacters have been used to designate like parts throughout the severalviews thereof, the apparatus comprises a tank or container T throughwhich the strip material S is fed in a sinuous path. The strip materialis reeved over and under respectively, a series 7 of upper rolls and 26and lower rolls R. The

rolls R are submerged in the solution, but the rolls 25 and 26 are abovethe surface of the solution. Abov the strip where it passes over eachroll 26, is a contact roll 25, by means of which electrical contact forthe plating current is made with the strip, instead of through roll 26,as in the practice usually followed hitherto. The rolls 25 arepreferably driven at the same peripheral speed so as to propel the stripsmoothly through the bath.

As the strip emerges from the bath for the last time, it passes througha squeegee assembly Q for removing the adhering electrolyte therefrom.An anode electroplating current is applied to a plurality of anodes Awhich are suspended in the bath between the vertical reaches of strip 5.The electrolyte is continuously circulatedpreferably, by removing aportion of it from tank T, filtering it, passing it through a heatexchanger (for imparting heat thereto or dissipating heat therefrom, asthe case may be, for securing the requisite electroplating temperature),and returning it to tank T ata point remote from the removal point. Theelectrolyte is returned to the electroplating tank in such manner as tocontinuously agitate the body of electrolyte in the tank adjacentAtheanodes and also to flush strip S above the level of the electrolyte fordis lodging adhering extraneous matter, both as it is entering andemerging from the electrolyte.

' Tank' and support constru tion Tank T is generally rectangular in formand comprises side walls ID, a bottom wall I I, and end walls 52. Forthe purpose of simplifying the illustration of the invention, I haveshown the strip as making only two complete passes through theelectrolyte. but it is to be understood that in actual practice the tankand other parts will be so designed as to cause the strip to make anysuitable number of passes through the electrolyte; in some instancesseveral hundred feet of strip material may be immersed in the tank atone time.

Communicating with the bottom of the tank is a circulation pipe I3,through which the electrolyte is fed to an electrolyte reconditioningand heat-exchanging apparatus of any suitable charactor, for purifyingthe electrolyte, restoring it to proper strength and bringin it to therequisite electroplating temperature.

The electrolyte is returned to the tank by way of a pair of spray pipesI4 and a pair of recirculation pipes I5. Spray pipes I4 may extendlongitudinally of the apparatus and they are joined by a plurality ofpairs of perforated pipes 66. The pipes of each pair are disposed ateither side of the path of travel of the strip S and the perforationsare directed downwardly at an angle to the horizontal for flushing thestrip and cleansing it of any adhering material.

Pipes 85 are each joined to a horizontal pipe I8 and as seen in Figure2, each pipe I8 extends longitudinally on either side of the path oftravel of the strip S. Joined to pipes I8 at spaced interare verticalpipes 19 each having perforations 26 therein that are directed towardthe middle of the tank. The electrolyte issuing from openings 25supplies fresh electrolyte adjacent the anodes and also keeps the bodyof the electrolyte in the tank in a state of constant agitation.

The contact roll assemblies and other parts of the mechanism are carriedupon a pair of horizontally extending angle members 22, which extendlongitudinally of the apparatus and rest on a plurality of verticalsupports 23. The mechanism preferably is supported upon the independentframework just described in order that the tank may not be subjected tostresses. The tank may, accordingly, be constructed of wood, concrete,brick, steel, hard rubber, or any other material or combination ofmaterial appropriate for use with the particular electrolyte employed,without special regard for supporting the assemblies and parts. To thisend, the bus bars and anodes are also supported upon an independentstructure.

Contact roll assembly The contact roll assembly as shown in Figures 1-3,inclusive, are similar in construction and therefore one of them will bedescribed.

Each assembly comprises a contact roll 25 proper hich is mounted formovement to and from an associated strip carrying roll 28.

Referring to Figures 1, 2, and 3, each contact roll 25 is journaled on ashaft 21 which is carried, at each end thereof, in an arm 28, which inturn is pivoted at 29 on a support 3|, carried by members 22. Shaft 21is insulated from members 28 by means of insulating backings 32; and anelectrical conductor 33, preferably of flexible design, is connected toeach end of shaft 21 for applying a cathode current to shaft 21 and tocontact roll 25.

Each strip carrying roll 26 is preferably made of steel and rubber(flexible) covered in order that it may effect intimate surfaceengagement between the strip S and the contact roll 25. However, thesurfacing of the carrying roll may be constructed of any other materialfound suitable for the purpose, such as micarta, asbestos, or othermaterials or combinations of materials. Each carrying roll is supportedon a shaft 35, which latter is journaled at each end in a bearing 36carried by the support 3I. A slinger 31 is positioned on shaft 35adjacent each side of the carrying roll; it, functions to keep theelectrolyte (with which the carrying roll is coated in normal operationby reason of the strip carrying it out of the tank) from creeping alongthe shaft and into the bearings.

Each contact roll 25 is resiliently urged toward a carrying roll,preferably by means of compression springs 39 that act upon extensions Hof the arms 28. Each extension 4| is apertured, and a stud 42, throughthe aperture and through spring 39 and has a nut 43 threaded thereon,against which the spring 39 abuts.

By adjusting nuts 43 of each contact roll assembly, the strip can begripped between surface portions of the contact roll 25 and the stripcarrying roll 26 in contact with the strip with variout degrees ofcompression. A second compression spring 44 is shown on each stud 42between extension M and support 3| for opposing the action of spring 39.and smoothing out the gripping action of the contact roll assemblies.

Each contact roll 25 is preferably hollow and provided with novel meansfor conducting the cathode current from the stationary shaft 21 to theroll. The contact roll construction, together with roll driving means,the submerged roll construction, and the anode and bus bar construction,are all fully disclosed in my copending application Serial No. 251,065,of which this application is a division.

Combined squeegee and centering roll assembly In feeding strip materialcontinuously, there is a possibility of camber or misalignment in thestrip after the component parts thereof have been welded or otherwisejoined together. Where such a strip is propelled through a plating tank,it will have a sidewise motion and will be damaged if its edges 'comeinto contact with the stationary parts of the plating machine; anunevenelectrodeposition will occur and the tank, itself, undergo damage.Accordingly, there is provided in the apparatus of the invention a novelstrip guiding or centering device which is fully automatic in operationand insures against the disadvantages just discussed.

Referring more particularly to Figures 3 to 8 inclusive, a pair ofsqueegee rolls III and H2 are journaled on a rocking base support H2;the latter is mounted for rocking movement in a trunnion H4 on astationary support H5. The other end of the rocking support H3 is guidedin a frame-like, stationary member I I6, which engages opposite edges H1and H8 of support H3, see Figure 6; roll H2 is journaled in the lefthand portion of base H3 at I20.

Roll III is journaled at H9 in a pair of arms I2I, which are pivoted atI22 to base H3. A

screw I23 actuated by a hand wheel I24, is threaded into each end ofbase H3 and acts upon a compression spring I25 to apply pressure topivot arms I2 I, for gripping the strip between secured to the support3|, extends the squeegees under selectively variable degrees ofpressure.

Squeegeerolls III and H2 are disposed in a side-by-side relationship inhousing H (see Figure 1), above the tank T, in order that electrolytesqueezed from the surface of the strip will freely gravitate back intothe tank. In order to Switch I42 is mounted for movement as a unitprevent electrolyte from working along the shafts supporting the rollsand finding its way to the bearings, each shaft is provided with a pairof slingers I21. The shafts for rolls III and H2 are provided withintermeshing gears I28 and I29, respectively, that are actuated by achain driven sprocket I3I carried by the shaft of roll II2. Sprocket I3Imay be driven to give rolls III and H2 a peripheral speed equal to thatof the other rolls by a synchronously driven motor.

I also preferably associate the novel centering means or strip guidingmeans of my invention with the squeegee rolls, but it is to beunderstood that, if desired, it may be associated with one of thecontact roll assemblies or may be duplicated and be applied to two ormore of the contact roll assemblies.

Means, actuated by the lateral movement of the strip material areprovided for causing base I I3 to be rotated about its axis I I4 in theproper direction to cause the moving strip to be restored to the properdirection of travel. To this end, a unitary electric motor and gear boxassembly I33 is mounted on stationary frame member H6 and provides adriving connection between the motor and a pair of guide screws I34which are journaled in frame IIB. Screws I34 are threaded into spacedframe portions I35 and I36 of base II3, see Figure 6; the arrangementbeing such that the rotation of the motor (which is reversible) willeffect synchronous rotation of screws I34 and thereby cause the lefthand endof base II3 (Figures 4 and 5) to be raised or lowered dependingupon the direction of rotation, effecting rocking movement of the entireassembly about pivot I I4 as an axis.

As shown in Figs. 6 and 7, in order to prevent binding between thescrews I34 and frame portions I35 and I36 when the frame rocks aboutpivot II4, the screws are threaded through a plate I35a having a concavebottom surface fitting on a convex surface in frame portion I35, and arelikewise threaded through a plate I360 having a convex top surfacefitting a concave surface in frame portion I36. A clearance is providedbetween the screws I34 and the frame portions I35 and I36. Accordingly,when the support II3 rocks about pivot II4, the misalignment on screwsI34 is taken care of by slipping of the plates I35a and I36a on theconvex and concave surfaces of frame portions I35 and I36 respectively.

The circuit for motor I33 is automaticaly controlled by a rod I38 thatcarries a lefthand finger in the form of a plate I39 and a right handfinger in the form of a plate I40. Rod I38 is mounted for reciprocatingmovement parallel to the axes of the rolls in base I I3 and fingers I39and I40 are adapted to be contacted by the side edges of the stripmaterial in its passage through the rolls. Contact of the strip withfingers I39 will effect a movement of rod I38 to the left, whereascontact of the strip with finger I40 will eifect a right hand movementof the rod. The movements of the rod just described are employed toclose the circuits in a limit switch assembly designated at I42, seeFigures 4 and 6, into whose housing the rod I38 projects.

rod I38 and its housing is provided with a pin I43. A bell crank leverI44 is pivoted on base H3 at I45;and is provided witha bifurcated endI46 which embraces this pin I43 and a bifurcated end I41 which embracesa pin I48 carried by stationary frame member H6. The arrangement of theparts is such that downward movement of the rocking base I I3 willeffect clockwise rocking movement of the lever I44 and move switch I42to the right (Figure 4). Upward movement of base II3 within frame 6 willeffect counter clockwise movement of lever I44 and movement of switchI42 to the left.

Summarizing the operation of the centering mechanism and assuming thatthe strip is being fed through the apparatus and is traveling too far tothe right, its edge contacts finger I40 and moves rod I38 to the right,which in turn causes switch unit I42 to energize motor I33 in adirection to cause screws I34 to effect a downward movement of base II3.This movement of base II3 rotates lever I44 in a clockwise direction,causing switch unit I42 to be moved to the right until it reaches apoint where it will break the circuit and shut down the motor. Thepurpose of movably mounting the limit switch I42 or other detectingdevice is to prevent overcorrection of the roll position, which wouldresult in an oscillating motion being imparted to the straight portionof the strip after the cambered part had passed.

With more particular reference to Figure 8, a suitable circuit is shownembodying the reversible motor I33 and its controlling unit or limitswitch indicated within rectangle I42; the armature and field of themotor are connected independently, as illustrated, across a line whichcarries direct current under proper voltage. The armature has reversibleconnections which determine its direction of rotation, depending uponthe positions of a plurality of automatic switches R82, R83, Lsz andLS3. When the R switches are closed and the L switches are open, thearmature turns in one direction; and upon closure of the L switches andopening of the "RP switches the direction of rotation is reversed. The Rswitches are operably connected for closure simultaneously with a switchRS1 when a coil Re is energized; and the L switches likewise areoperably connected with a switch Lsi and are actuated by a coil Lc.Normally, that is, when the strip is running true, all of the switchesand the limit switch I42 occupy the positions illustrated in Fig. 8.

The switch assembly I42 embodies a pair of double contact switches R andL comprising spaced pairs of contacts cooperating, respectively, withcontact disks Rd and Ld which are carried within the switch assembly by,and shiftable axially with, the strip-actuated rod I38. The disks,however, are movable slightly in both directions along the rod againstany suitable yielding means. such as compression springs I4I that aredesigned to normally urge the disks to definite positions relative tothe rod, such positions being illustrated in Fig. 8.

The contact elements of the switches R and L are associated with therespective coils, Re and Lo, in such a manner that, in the positionillustrated in Fig. 8, both coils are short-circuited and hencede-energized and the motor I33 is stationary; that in one direction ofmovement of the rod I38 (righthand), th coil Rc is ener base H3.

gized while the coil Lc remains shorted; and that in the other directionof movement of rod I38 (lefthand), the coil Rc becomes short-circultedand the coil Lc energized. Suitable current adjusting resistors RT andLT are interposed in the respective branches of the circuit.

Assuming that the rod I38 has been moved to the right through contact ofthe strip with finger I40, this will open the normally closed contactsand close the normally open contacts of switch R, thus energizing themotor in such a way as to drive the lefthand end (Figures 4 and 5) ofbase H3 downwardly on screws I34. Downward movement of the left portionof base H3 causes the limit switch unit I42 to be shifted to the rightthrough the action of lever I and this will reopen the normally opencontacts and reclose the normally closed contacts of the switch R.Reclosing the normally closed contacts will short-circuit the coil RC,thus de-energizing the coil and stopping the motor. Should the stripcontinue to shift to the right after the cycle of operations justdescribed has been completed, the entire sequence of action will berepeated until the roll assembly has been lowered sufliciently tocounteract the misaligning tendency of the camber of the strip.

When the cambered part of the strip has passed the squeegee rollassembly, the strip will feed to the left because the left hand end ofthe roll assembly is lowered as the result of the operation previouslydescribed. The strip will then engage finger I39 and carry rod I38 tothe left. This will energize the motor by means of the limit switch unitL in a manner similar to that previously described except that thedirection of the rotation of the motor will be reversed so as to effectupward movement of the lefthand end of base H3. This in turn will causethe limit switch unit I42 to be shifted to the left to stop the motorand arrest upward movement of the Should the strip continue to feed tothe left, the sequence of operations will be repeated until the sidewisemotion of the strip has been corrected. The manner of correction formovement of the strip to the left of its true center position is thoughtto be obvious in view of the above, and hence is not explained indetail. It is therefore apparent that the feed of the strip isautomatically and accurately controlled at all times withoutovercorrection and without feeding the strip past a center position.

The invention may be carried out by other suitrhle and/or modifiedapparatus. For examle, the squeegee roll support has been illustratedLild described as being mounted for rocking movement about a horizontalaxis, but, if desired, it may be mounted for rocking movement about avertical axis and the actuating means and control mechanism thereformodified to effect proper centering of the strip. Also, rod

iiiii and fingers I39 and M0 have been illustrated as being carried bythe squeegee roll support H3, but, if desired they may be so disposed asto cooperate with the strip in a region other than ad- Jacent thesqueegee roll assembly. For instance, they may be located adiacent oneof the contact rolls if desired, without departing from the spirit of myinvention so long as movements of the squeegee roll support are suitablycorrelated therewith to effect a control similar to that effected bythe'mechanism of Figures 4 to 8, inclusive.

I claim:

1. In a combined squeegee and guide roll assembly for propelling stripmaterial through an electrotreating tank, a support, a pair of parallelrolls mounted for rotation on said support, means mounting said supportfor rocking movement, power means for actuating said support, fingermeans mounted adjacent the path of travel of the strip material andadapted to be contacted by a side edge thereof for causing said powermeans to actuate said support in one direction, and a second fingermeans cooperating with the other side edge of the strip material foreffecting opposite movement of said support, and mechanism actuated inaccordance with movement of said support for causing said power means tobrin said support to rest after the latter has been moved apredetermined distance by said power means in response to actuation byeither of said fingers.

2. In an apparatus as defined in claim 1, electromagnetic meanscontrolled by said finger means and actuating said power means.

3. In an apparatus for electrotreating strip material, a plurality ofrolls for guiding the strip through the apparatus, at least one of saidrolls being journaled in a rockable frame mounted on a stationarysupport, means for rocking said frame about an axis perpendicular to theaxis of said one roll, control means automatically actuated by lateralmovement of the strip for operating said rocking means to rock saidframe and maintain said strip properly centered relative to said oneroll as said strip passes thereover, and means actuated by said rockingmovement of the frame for stopping said rocking means when said rockingframe has moved a; predetermined amount.

4. In an apparatus for electrotreating strip material having anelectrolytic tank within which the strip is adapted to beelectrotreated, a plurality of rolls for guiding the strip through thetank, at least one of said rolls being journaled in a rockable framemounted on a stationary support, means for rocking said frame about anaxis perpendicular to the axis of said one roll, actuating means onopposite sides of the path of said strip and adapted to be contacted bythe side edges of said strip for operating the rocking means to rocksaid frame for raising the end of the roll at the side of the stripbeing contacted, and control means actuated by a predetermined amount ofrocking movement of the frame in either direction for stopping operationof said rocking means.

JOHN S. NACHTMAN.

